This invention relates to a machine for forming cylindrical bales of crop material for example, such as hay or the like, and in which the bale is formed between the rearwardly moving upper run of a lower conveyor and the forwardly moving lower run of an upper conveyor. The upper conveyor includes a plurality of side-by-side arranged individual belts and which are trained around supporting rollers. This upper conveyor is maintained around the bale as the latter grows in size. The tensioning of the upper conveyor or compacting belt as it is commonly known is accomplished by the subject matter shown in the co-pending patent application Ser. No. 69,997 filed Aug. 27, 1979 and entitled "Cylindrical Bale Forming Machine Having Hydraulic Control Means For Controlling The Bale Density", which has been assigned to an assignee common with the present invention.
The present invention is an improvement over the U.S. Pat. No. 4,150,527 issued Apr. 24, 1979 and entitled "Machine for Forming Cylindrical Hay Bales" and which discloses a pair of rollers on which the bale is supported and which act to penetrate the bale as it is being formed to thereby control the density of the bale.
In machines of this general character, the effect of friction between the material and the side walls of the machine can be detrimental to bale formation, that is to say, when high moisture content conditions of the crop are encountered, an excessive friction between the material and the side walls produces excessive compacting belt driving tension. The placement of the material as it enters the baling chamber for example to one side or the other also creates excessive side sheet friction with resulting excessive compacting belt tension and bales of undesirably high density. In crops which are baled at high moisture content, the side sheet friction and the upper belt tension are inter-related by the Bulk-modulus or Poissons effect, which effect tends to produce a feedback relationship between the compacting belt driving tension and the side sheet friction which in turn produces bales of excessive bale density and corresponding compacting belt driving tension.
The present invention is an improvement over the U.S. Pat. No. 3,914,926 issued Oct. 28, 1975 and which is assigned to an assignee common with the present application. The device shown in that patent utilizes large tension springs for maintaining the tension in the upper compacting belts and also utilizes a one-piece conveyor which extends from the pickup unit at the front of the machine, rearwardly to the rear end of the machine adjacent the discharge gate.
Generally, in such baling machines, hay is received by the baler between a feed roller and the conveying belt and is pressed into a flat thin mass from which it passes to a core forming area where it is rolled between the upper flight of the conveyor belt and the lower oppositely moving flight of the compacting belt. Thereafter, the thin mass of hay is rolled about the core into a bale which continues to increase in size until the desired size is achieved. During its formation, the bale is formed in a zone in which it is confined between the conveyor belt and the upper compacting belt.